Faucets with sensors for the automatic control of the flow of fluid through the faucet are well known in the art. For example, U.S. Pat. No. 4,741,363 issued to Hu on May 3, 1988, and assigned to the owner of the present invention, illustrates a fluid faucet having a flow control circuit that utilizes an infrared sensor to permit the flow of water through the faucet when an object is close to the faucet. The transmitter and receiver for the infrared energy utilized to sense the presence of the object are mounted on the body of the faucet and are directed toward an area beneath the outlet of the faucet. The orientation of the transmitting and receiving elements is critical for proper detection operation of the faucet. In order to detect the hands of a user, and in order to avoid spurious operation of the faucet in response to signals reflected off of nearby articles, the design of the support structure for the transmitting and receiving elements must be carefully considered, as discussed in U.S. Pat. No. 4,894,874 issued to Wilson on Jan. 23, 1990. It is also known in the art to take measures to ensure that the sensor orientation is securely fixed in order to prevent movement of the sensor due to vandalism or accident. See for example U.S. Pat. No. 5,586,573 issued to Nortier on Dec. 24, 1996, wherein the sensor is prevented from moving by a pin 54.
It is also known to provide automatic faucets with a variety of control and operation features. For example U.S. Pat. No. 4,941,219 issued to Van Marcke on Jul. 17, 1990, illustrates a DC powered automatic faucet having a low voltage battery sensor circuit. U.S. Pat. No. 4,894,874, cited above, describes a light emitting diode mounted on the faucet and connected electrically to glow dimly when power is supplied to the faucet control circuitry, and to glow brightly when the control means for the faucet receives an infrared light signal from a user's hands. Each of the above cited prior art patents is incorporated by reference herein.
In spite of the variety of features available on prior art automatic faucets, no single faucet design provides sufficient flexibility for installation in a wide variety of locations. For example, the particular environment in which a faucet is installed may contain surfaces that act as reflectors for the sensing signal, thereby creating erratic operation of the faucet. Such surfaces may include the variety of sink bowls on which the faucet may be mounted, or a mirror or other metallic surface in the area of the faucet installation. Additionally, the availability of alternating current (AC) electricity to power the automatic faucet is often uncertain, such as when the faucet is installed at a location such as in a park or recreation facility. Prior art automatic faucets operating on alternating current are not interchangeable with those operating on battery powered direct current (DC) since the operating logic and control system for an AC and a DC solenoid valve are different and are not compatible. What is needed is a design for an automatic faucet that provides additional flexibility to accommodate a variety of installation parameters.